Food choices often represent trade-offs. From the consumer to the producer, risks are weighed and decisions made every day – a process that requires information, context and often luck. Yet the challenges of an increasing population, nutrition-related chronic diseases, poverty, volatile food price markets, inequity, urbanisation, market integration, habitat loss, resource depletion and persistent hunger mean we need more than partial information to make the best food choices.

So how do we get a more complete picture to help inform our decisions on nutrients, foods and diet? Looking at diets in terms of their long-term sustainability is an option. We need to go beyond considering a diet as simply a way to place nutrients in our bodies.

Sustainable diets are characterised by low environmental impacts, contributions to food and nutrition security, as well as healthy lives for present and future generations. They respect ecosystems and are culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy; and optimise the use of natural and human resources. They consider biodiversity of crops and varieties of foods – similar to the diversification of an investment portfolio. They are about options for our future.

Demand for nutritious food is increasing. We are aware that 9 billion people will need to be fed every day by 2050 – without causing additional resource depletion and damage on our planet. Every day that goes by we are witnessing population growth coinciding with more poorly nourished people. The stunted child, the overweight adolescent, the hidden hunger of micronutrient deficient mothers who may also be overweight are all manifestations of the phenomenon of the triple burden of malnutrition: undernutrition, hidden hunger and obesity.

This triple burden of malnutrition affects our world economy – from demand of high-fat, high-sugar foods to increased healthcare costs. Worsening diet-related chronic disease and overnutrition has led to an array of initiatives. Examples include the Danish "fat tax" and restrictions on soft drinks in New York City. These efforts are attempting to address the very real transfer of health costs to the health sector of changing diets and lifestyles.

Research is yielding clues regarding as to what sustainable diets are and how can they be encouraged. The understanding of sustainable diets is as relevant to the challenges of undernutrition as it is with dietary transition and nutrition-related chronic diseases linked closely to overweight and obesity.

Sustainable diets represent a move away from focusing on single nutrients and foods as a basis for good nutrition towards studying food systems in a comprehensive sustainable manner. It is possible that a greater emphasis on food systems that embrace the sustainable diet concept will reap nutritional and livelihood benefits for small farmers, food manufacturers and consumers across the globe.

We are already seeing efforts on the part of some governments and regulatory authorities to examine the carbon and water costs of foods and to adjust pricing policies and dietary guidelines for a more sustainable future. Sustainable food systems must also intelligently manage the diminishing natural resources we have.

It is also about the choices we make as individuals and consumers to assess the trade-offs in terms of cost, acceptability, nutrition and minimising the risk of nutrition-related chronic diseases. Food marketers and distribution systems will gain a better understanding of the needs of consumers and the environment and promote a healthier more sustainable food system.

There is an urgent need to research and advance innovative strategies to understand, measure and promote sustainable diets, as well as understand the role of agricultural biodiversity in human health and nutrition. We need to capture the rich cultural history of our foods so it is not lost in our mission to intensify agricultural production and promote value chains that unnecessarily change what is already there.

We also need to understand the behaviours that govern choices, as well as the access and cost concerns around diets to provide better and clear recommendations.

Let's look ahead to the next set of challenges such as the post-2015 Millennium Development Goals, the UN-led Zero Hunger Challenge and the reduced stunting target set by prime minister David Cameron at the London Olympics.

We have an opportunity to look beyond another global target to engaging the business community and the scientific community to approach complicated issues with thoughtful negotiated approaches, that link the needs of consumers and farmers.